Spine Surgery Retractor System and Related Methods

ABSTRACT

A retractor system and related methods for use in spinal surgery procedures, including but not limited to fusing or repairing damaged or deteriorated intervertebral discs or vertebral bodies in the lower lumbar levels. The retractor system includes a plurality of blade assemblies coupled to a handle assembly, wherein each of the blade assemblies may be independently adjusted (e.g. length blade and/or blade angulation and/or blade rotation relative to the handle assembly) to provide unprecedented customization of an operative corridor extending to the surgical target site of the patient such that any number of spinal surgery procedures may be undertaken by a surgeon, including but not limited to spinal fusion procedures at the L5-S1 disc space.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a non-provisional application claiming thebenefit of priority under 35 U.S.C. 119(e) from commonly owned andco-pending U.S. Provisional Application Ser. No. 62/487,349, filed onApr. 19, 2017, and U.S. Provisional Application Ser. No. 62/487,329,filed on Apr. 19, 2017, and are entitled “Spine Surgery Retractor Systemand Related Methods,” the entire contents of which are herebyincorporated by reference into this disclosure as if set forth fullyherein.

FIELD

The present disclosure relates generally to the field of surgery and,more specifically, a retractor system for use in spine surgeryprocedures, including but not limited to repairing damaged ordeteriorated vertebrae at the lower lumbar levels, such as in the L5-S1intervertebral space.

BACKGROUND

The vertebral column is the central pillar of the body. It is agenerally flexible column that bears tensile and compressive loads,permits bending motions, and provides an attachment site for ribs,muscles and other structures. The vertebral column includes irregularbones called vertebrae that are separated by fibrocartilaginousstructures known as intervertebral discs. There are seven vertebral,twelve thoracic, five lumbar, five sacral, and four coccygeal vertebrae.A typical vertebra consists of a rounded anterior body and a posteriorvertebral arch that together form a protective structure around thevertebral canal that contains the spinal cord.

The intervertebral discs can be damaged or undergo degeneration, whichoften results in painful and sometimes debilitating nerve impingementsyndromes. It is sometimes necessary to surgically replace the nativedisc with prosthetic disc implants to relieve the pain, restore thefunctional mechanics of the vertebral column, and promote fusion betweenadjacent vertebral bodies. Procedures such as total disc arthroplasty(disc replacement) have used a direct anterior approach orthogonal tothe midline of the vertebral body, but such procedures requireunfettered anterior spinal exposure for precise midline placement of theprosthetic disc. The major vascular structures that run along theanterior spine must be mobilized to achieve this exposure, whichtypically requires the assistance of a vascular surgeon. The procedurealso causes significant surgical disruption of the anterior annularelement around the disc.

Bertagnoli has described an anterolateral transpsoatic approach (ALPA)for implantation of prosthetic disc replacement devices. The patient ispositioned in a supine position on the operating table, with the arms inabduction. The target disc level is localized through bi-planarfluoroscopy, and an inflatable bladder is placed beneath the level ofinterest to permit additional lordosis. An anterolateral incision ismade on the left side for access to lumbar intervertebral spaces, whilethe incision is made on the right side for access to L5-S1. The fasciaof the external oblique muscle is opened along the direction of itsfibers and the muscle is split. The retroperitoneal space is entered andthe peritoneal sac mobilized away from the overlying fascia to developan operative pathway along the anterior aspect of the psoas muscle tothe lateral aspect of the intervertebral space. The target zone forannulotomy is from the one o'clock to three o'clock position above theL5-S1 level, which leaves the anterior longitudinal ligament intact andavoids mobilizing the iliac vessels. At the L5-S1 level the targetannulotomy zone is from theeight o'clock to ten o'clock position withmobilization of the iliac vessel toward the midline. Injury to the leftiliac vessel is an unfortunate complication of such procedures.Additional information about anterolateral approaches to spinal surgeryat the L4-L5 level is found in Bertognali et al, U.S. Pat. No.7,326,216.

A minimally invasive procedure promoted by Nuvasive, Inc. uses a directlateral, retroperitoneal approach to access the intervertebral discsabove the L5-S1 level with minimal muscular disruption. The patient isplaced in a lateral decubitus position and the direct lateral incisionis made in the axillary line. Another incision is made posterior to thelateral border of the erector spinae muscle, and finger dissection isconducted through this opening to the retroperitoneal space. The indexfinger of the surgeon sweeps the peritoneum anteriorly and palpates thepsoas muscle. A dilator instrument is then introduced through the directlateral incision and the index finger then guides the dilator instrumentto the psoas muscle. The fibers of the psoas muscle are then split usingblunt dissection and EMG monitoring to minimize damage to the nerves ofthe lumbar plexus that run through the posterior psoas muscle. A tissuedistraction and tissue retraction assembly are then used to helpestablish an operative corridor to the direct lateral aspect of theintervertebral space at about the 3 o'clock position, as shown in U.S.Pat. No. 7,207,949. The direct lateral retroperitoneal approach to theL5-S1 space has not been possible because the anterior superior iliacspine obstructs a direct lateral approach to the L5-S1 intervertebralspace. Hence approaches to the L5-S1 space typically use a standardanterior approach. For a laterally positioned patient, an extremelylarge sigmoidal incision has been required, with subsequent reflectionof all the overlying musculature to expose the L5-S1 space.

It would therefore be useful to provide a minimally invasive approach tothe L5-S1 space that minimizes injury to the blood vessels and nervesaround the vertebral bodies. It would also be helpful to perform such aprocedure in a manner that minimizes retroperitoneal scarring and damageto other body structures. Minimally invasive surgical approaches to theintervertebral spaces in the past have also been limited by the need toinsert the prosthetic disc implant either into the front portion,posterior portion, or the side of the disc space to achieve stableplacement of the prosthetic implant. It would therefore be useful tohave a procedure that could avoid such a limitation at any vertebrallevel.

The present disclosure is directed to a retractor system specificallydesigned and optimized to address the various unmet needs associatedwith performing spine surgery procedures at the L5-S1 disc space.

SUMMARY

A retractor system is disclosed that addresses the previously unmetneeds through the combination of a plurality of blade assemblies coupledto a handle assembly, wherein each of the blade assemblies is configuredto provide unprecedented customization of an operative corridorextending to the surgical target site of the patient such that anynumber of spinal surgery procedures may be undertaken by a surgeon,including but not limited to spinal fusion procedures at the L5-S1 discspace . The retractor system may be used according to the teachings ofU.S. Pat. No. 9,451,940 (invented by Dr. Scott Spann of Austin Tx.,inventor of the present application), which is attached hereto asExhibit A and forms part of this provisional patent application.

BRIEF DESCRIPTION OF THE DRAWINGS

Many advantages of the present disclosure will be apparent to thoseskilled in the art with a reading of this specification in conjunctionwith the attached drawings, wherein like reference numerals are appliedto like elements and wherein:

FIG. 1 is an elevated perspective view of one example of a surgicalretractor system with retractor blades in a generally open configurationaccording to one aspect of the disclosure;

FIG. 2 is a top plan view of the surgical retractor system of FIG. 1;

FIG. 3 is a side plan view of the surgical retractor system of FIG. 1;

FIG. 4 is a front plan view of the surgical retractor system of FIG. 1;

FIG. 5 is an elevated perspective view of another example of a surgicalretractor system with retractor blades in a generally closedconfiguration according to one aspect of the disclosure;

FIG. 6 is a front view plan of the surgical retractor system of FIG. 5;

FIG. 7 is a top plan view of the surgical retractor system of FIG. 5;

FIG. 8 is a side plan view of the surgical retractor system of FIG. 5;

FIG. 9 is an elevated perspective view of an example of a retractor bodyforming part of the surgical retractor system of FIG. 5;

FIG. 10 is a top plan view of the retractor body of FIG. 9;

FIG. 11 is an exploded perspective view of the retractor body of FIG. 9;

FIG. 12 is an elevated perspective view of a base member forming part ofthe retractor body of FIG. 9;

FIG. 13 is a bottom perspective view of the base member of FIG. 12;

FIG. 14 is a top plan view of the base member of FIG. 12;

FIG. 15 is a partially exploded elevated perspective view of theretractor body of FIG. 9;

FIG. 16 is a bottom perspective view of a cap member forming part of theretractor body of FIG. 9;

FIG. 17 is a partially exploded elevated perspective view of theretractor body of FIG. 9;

FIG. 18 is an elevated perspective view of a first retractor bladeforming part of the surgical retractor system of FIG. 5;

FIG. 19 is a front plan view of one example of a first blade assemblyforming part of the surgical retractor system of FIG. 5;

FIG. 20 is a side plan view of the first retractor blade assembly ofFIG. 19;

FIG. 21 is a rear elevated perspective view of an upper portion of thefirst retractor blade assembly of FIG. 19;

FIG. 22 is a top plan view of the first retractor blade of FIG. 18;

FIG. 23 is a front plan view of an example of an anchor pin forming partof the first retractor blade assembly of FIG. 19;

FIG. 24 is a front perspective view of a blade holder assembly coupledwith a second retractor blade, forming part of the surgical retractorsystem of FIG. 5 according to an aspect of the disclosure;

FIG. 25 is a rear perspective view of the blade holder assembly coupledwith the second retractor blade of FIG. 24;

FIG. 26 is a side plan view of the blade holder assembly coupled withthe second retractor blade of FIG. 24;

FIG. 27 is a side plan view of the blade holder assembly of FIG. 24;

FIG. 28 is a top plan view of the blade holder assembly of FIG. 24;

FIG. 29 is a front elevated perspective view of the blade holderassembly of FIG. 24;

FIG. 30 is a front elevated exploded perspective view of the bladeholder assembly of FIG. 24;

FIG. 31 is an elevated perspective view of an example of a blade holderforming part of the blade holder assembly of FIG. 24;

FIG. 32 is a top plan view of the blade holder of FIG. 31;

FIG. 33 is an elevated perspective view of a tulip forming part of theblade holder assembly of FIG. 24;

FIG. 34 is a top plan view of the tulip of FIG. 33;

FIG. 35 is a bottom perspective view of a tulip assembly forming part ofthe blade holder assembly of FIG. 24;

FIG. 36 is a rear perspective view of an example of a blade adjustmentgear forming part of the blade holder assembly of FIG. 24 engaged withthe second retractor blade of FIG. 24;

FIG. 37 is a front perspective view of a blade holder assembly coupledwith a third retractor blade, forming part of the surgical retractorsystem of FIG. 5 according to an aspect of the disclosure;

FIG. 38 is a side plan view of the blade holder assembly coupled withthe third retractor blade of FIG. 37;

FIG. 39 is a rear perspective view of the blade holder assembly coupledwith the third retractor blade of FIG. 37;

FIG. 40 is a side plan view of the blade holder assembly of FIG. 37;

FIG. 41 is a top plan view of the blade holder assembly of FIG. 37;

FIG. 42 is a front elevated perspective view of the blade holderassembly of FIG. 37;

FIG. 43 is a front elevated exploded perspective view of the bladeholder assembly of FIG. 37;

FIG. 44 is an elevated perspective view of an example of a blade holderforming part of the blade holder assembly of FIG. 37;

FIG. 45 is a top plan view of the blade holder of FIG. 44;

FIG. 46 is an elevated perspective view of a tulip forming part of theblade holder assembly of FIG. 37;

FIG. 47 is a top plan view of the tulip of FIG. 45;

FIG. 48 is a bottom perspective view of a tulip assembly forming part ofthe blade holder assembly of FIG. 37;

FIG. 49 is a rear perspective view of an example of a blade adjustmentgear forming part of the blade holder assembly of FIG. 37 engaged withthe third retractor blade of FIG. 37; and

FIG. 50 is a schematic cross-sectional view of the abdomen at the levelof the L5-S1 intervertebral space illustrating left anterolateraldisplacement of the peritoneum and the right anterolateral introductionof first and second blades of the surgical retractor system of FIG. 5,with the right and left iliac vessels retracted away from the anteriorspine.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Illustrative embodiments of the invention are described below. In theinterest of clarity, not all features of an actual implementation aredescribed in this specification. It will of course be appreciated thatin the development of any such actual embodiment, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which will vary from one implementation toanother. Moreover, it will be appreciated that such a development effortmight be complex and time-consuming, but would nevertheless be a routineundertaking for those of ordinary skill in the art having the benefit ofthis disclosure. The surgical retractor system disclosed herein boasts avariety of inventive features and components that warrant patentprotection, both individually and in combination.

With reference to FIGS. 1-4, a retractor system 10 of the presentinvention includes a handle 12, a first adjustable blade assembly 14, asecond adjustable blade assembly 16, and a third adjustable bladeassembly 18. First blade assembly 14 includes a first blade 20 coupledto a first articulation assembly 22 that is, in turn, coupled to an arm24 extending from the handle 12. Second blade assembly 16 includes asecond blade 26 coupled to a second articulation assembly 28 that is, inturn, coupled to an arm 30 extending from the handle 14. Third bladeassembly 18 includes a third blade 32 coupled to a third articulationassembly 34 that is, in turn, coupled to a pair of parallel arms 35extending from the handle 12. As shown in FIG. 3, handle 12 includes agenerally horizontal section 12H and generally vertical section 12V,each of which may be dimensioned to be manually grasped by a surgeon orphysician's assistant (PA) intra-operatively and may also includefeatures to secure the handle 12 in a stationary manner relative to thepatient and/or the operating table.

The first articulation assembly 22 includes a first arm 36, a second arm38, and a lock bolt 39. The first arm 36 includes an articulationhousing 40 at a first end and an elbow joint element 42 at a second end.The articulation housing 40 is dimensioned to receive a balled element43 extending from the arm 24 of the handle 12. The second arm 38includes an articulation housing 44 at a first end and an elbow joint 46at a second end. The articulation housing 44 is dimensioned to receive aballed element 45 extending from a first blade holder assembly 47coupled to the first blade 20. The lock bolt 39 extends through axiallyaligned apertures in the elbow joints 42, 46 and includes an enlargedregion 39 a dimensioned to be manually rotated by a user to lock orunlock the articulation assembly 22. More specifically, the manualrotation of the lock bolt 39 will serve to lock or unlock the elbowjoints 42, 46, the articulating joint formed between the articulationhousing 40 and the balled element 43 forming part of the arm 24 of thehandle 12, and the articulation joint formed between the articulationhousing 44 and the balled element 45 extending from the first bladeholder assembly 47. Each articulation joint so formed is capable ofarticulating in multiple planes and also rotationally, whichcollectively provides a high degree of flexibility in positioning thefirst blade 20 relative to the handle 12, second blade 26 and thirdblade 32 to create a customized operative corridor.

The second articulation assembly 28 includes a first arm 56, a secondarm 58, and a lock bolt 59. The first arm 56 includes an articulationhousing 60 at a first end and an elbow joint element 62 at a second end.The articulation housing 60 is dimensioned to receive a balled element63 extending from the arm 30 of the handle 12. The second arm 58includes an articulation housing 64 at a first end and an elbow joint 66at a second end. The articulation housing 64 is dimensioned to receive aballed element 65 extending from a second blade holder assembly 67coupled to the second blade 26. The lock bolt 59 extends through axiallyaligned apertures in the elbow joints 62, 66 and includes an enlargedregion dimensioned to be manually rotated by a user to lock or unlockthe articulation assembly 28. More specifically, the manual rotation ofthe lock bolt 59 will serve to lock or unlock the elbow joints 62, 66,the articulating joint formed between the articulation housing 60 andthe balled element 63 forming part of the arm 30 of the handle 12, andthe articulation joint formed between the articulation housing 64 andthe balled element 65 extending from the second blade holder assembly67. Each articulation joint so formed is capable of articulating inmultiple planes and also rotationally, which collectively provides ahigh degree of flexibility in positioning the second blade 26 relativeto the handle 12, first blade 20 and third blade 32 to create acustomized operative corridor.

The third articulation assembly 34 includes a lock bolt that extendsperpendicularly through the pair of parallel arms 35 that extendlongitudinally away from the handle 12 along the longitudinal axis ofthe handle 12, as well as through a bore formed through part of a thirdblade holder assembly 73 coupled to the third blade 32. The lock bolt 37of the third articulation assembly 34 may be operated with a wrench,driver, or other instrument capable of rotating the lock bolt 37clockwise or counterclockwise to tighten or loosen, respectively, thearticulation joint so formed. Based on the perpendicular positioning ofthe lock bolt 37, the degree of articulation of the third blade 32 islimited to the plane of the longitudinal axis of the handle 12, that is,the third blade 32 may be selectively tilted relative to the handle 12but not rotated or positioned outside the plane of the longitudinal axisof the handle 12. The uni-planar articulation joint of the thirdarticulation assembly 34 provides a lower yet important degree offlexibility in positioning the third blade 32 relative to the handle 12,first blade 20 and second blade 26 to collectively create a customizedoperative corridor.

The first, second and third blades 20, 26, 32 may be constructed havingany number of suitable features and dimensions. In one embodiment, thefirst blade 20 and second blade 26 are generally identical inconstruction, each dimensioned such that, in use, a proximal end (20Pand 26P in FIG. 4) will extend above the skin of the patient and adistal end (20D and 26D in FIG. 4) will extend to a location proximatethe surgical target site. The third blade 32 is of similar constructionto the first blade 20 and second blade 26, with the exception that thethird blade 32 includes longitudinal apertures 69 for receiving K-wiresor other fixation elements to dock or otherwise temporarily register thedistal end of the third blade 32 relative to the surgical target site(e.g. by extending the fixation element into the adjacent vertebralbodies and/or the disc space). The third blade 32 also differs from thefirst and second blades 20, 26 in that the distal end (32D in FIG. 4) ofthe third blade 32 includes a notch 71 extending along the perimeter asbest viewed in FIG. 4. The blades 20, 26, 32 may be constructed from anynumber of suitable materials, including but not limited to metal, carbonfiber, plastic or any combination.

The length of the blades 20, 26, 32 that extends between a skin incisionand the surgical target site may be selectively adjusted through the useof the respective blade holder assemblies 47, 67, 73. First blade holderassembly 47 includes a collar 75 having an aperture dimensioned toslidably receive the first blade 20 therethrough, as well as a screw 76for selectively locking or unlocking the first blade 20 relative to thecollar 75. Second blade holder assembly 67 includes a collar 85 havingan aperture dimensioned to slidably receive the second blade 26therethrough, as well as a screw 86 for selectively locking or unlockingthe second blade 26 relative to the collar 85. Third blade holderassembly 73 includes a collar 95 having an aperture dimensioned toslidably receive the third blade 32 therethrough, as well as a screw 96for selectively locking or unlocking the third blade 32 relative to thecollar 95. In this manner, the length of each blade 20, 26, 32 extendingbetween skin incision and surgical target site may be independentlyadjusted such that the distal ends 20D, 26D, 32D may be positioned withdifferent lengths to accommodate an optimal location relative to thesurgical target site. This may be especially advantageous duringsurgeries wherein the surgical approach is at an angle relative to thesurgical target site, such as (by way of example only) during aretroperitoneal surgical approach to the L5-S1 disc space, whichmethodology is explained in greater detail U.S. Pat. No. 9,451,940, thecomplete disclosure of which is incorporated by reference into thisdisclosure as if set forth fully herein.

FIGS. 5-49 illustrate a surgical retractor system 110 according toanother embodiment of the disclosure. With initial reference to FIGS.5-8, the surgical retractor system 110 of the present example includes aretractor body 112, a first blade assembly 114, a second blade assembly116, and a third blade assembly 118. As will be described in furtherdetail below, the first blade assembly 114 includes a first retractorblade 120 and a first blade holder assembly 122 including a blade holder124 integrally formed with (or otherwise attached directly to) thedistal body portion 136 of the retractor body 112 (see, e.g. FIG. 17).The second blade assembly 116 includes a second retractor blade 126 anda second blade holder assembly 128 movably coupled to a first arm 137 ofthe retractor body 112. More specifically, the second blade holderassembly 128 may be caused to translate longitudinally along and/orrotate about the first arm 137 which, when also including a pivotingmotion within the blade holder assembly 128 as well as verticaladjustment capability of the second retractor blade 126, allows the userto position the second retractor blade 126 in any suitable manner tocreate a customizable operative corridor. The third blade assembly 118includes a third retractor blade 130 movably coupled to a second arm 139of the retractor body 112. More specifically, the third blade holderassembly 132 may be caused to translate longitudinally along and/orrotate about the second arm 139 which, when also including a pivotingmotion within the blade holder assembly 132 as well as verticaladjustment capability of the third retractor blade 130, allows thesurgeon to position the third retractor blade 130 in any suitable mannerto create a customizable operative corridor. By way of example, theretractor body 112 has a longitudinal axis 1 extending therethrough thateffectively divides the retractor body into two sides (e.g. a first sideand a second side).

The blades 120, 126, 130 may be constructed from any number of suitablematerials, including but not limited to metal, carbon fiber, plastic orany combination. The length of the blades 120, 126, 130 that extendsbetween a skin incision and the surgical target site may be selectivelyand independently adjusted through the use of the respective bladeholder assemblies 122, 128, 132. As such, the distal ends of each of theblades may be positioned with different lengths to accommodate anoptimal location relative to the surgical target site. This may beespecially advantageous during surgeries wherein the surgical approachis at an angle relative to the surgical target site, such as (by way ofexample only) during a retroperitoneal surgical approach to the L5-S1disc space, which methodology is explained in greater detail U.S. Pat.No. 9,451,940, the complete disclosure of which is incorporated byreference into this disclosure as if set forth fully herein.

FIGS. 9-16 illustrate an example of the retractor body 112 forming partof the surgical retractor system 110 according to one aspect of thedisclosure. By way of example, the retractor body 112 includes aproximal body portion 134, a distal body portion 136, and first andsecond retractor arms 137, 139 coupled with and extending from thedistal body portion 136. In the example shown and described herein, theproximal body portion 134 are separate elements joined by a hinge joint138, however other formations are possible.

By way of example, the proximal body portion 134 has a proximal end 140,a distal end 142, and an enlarged cutout section 144 that primarilyfunctions to reduce the amount of material used (and therefore theweight of the retractor). By way of example, the proximal body portion134 may also be considered as a “handle” element to allow for manualmanipulation by a user. In addition, the retractor body 112 may furtherinclude a proximal connector 146 coupled to and extending proximallyfrom the proximal end 140. The proximal connector 146 of the presentexample is a generally rectangular member including a threaded post 148extending distally therefrom and configured to be threadedly receivedwithin a proximal threaded aperture 150 formed within the proximal end140 of the proximal body portion 134 (however other engagementmechanisms are possible, including but not limited to snap-fit, welding,and integral formation). The proximal connector 146 further includes anupper-facing cutaway 152 positioned at the proximal end which itselfincludes a recess 154 formed therein, and a lower-facing recess 156exending laterally and/or longitudinally across the inferior surface ofthe proxial connector 146. By way of example, the upper-facing cutaway152, recess 154, and/or lower-facing recess 156 may facilitate enagementof the retractor body 112 with additional instrumentation and/orstructure (e.g. articulating arm) to secure the retractor body 112 in astationary manner relative to the patient and/or the operating table.

The distal end 142 includes a flange 158 extending distally from thedistal end 142, the flange 158 forming part of the hinge joint 138connecting the proximal body portion 134 to the distal body portion 136.The flange 158 includes a transverse through-hole 160 extendinglaterally through the flange 158 and dimensioned to receive the shaft178 of the hinge pin 176 therein. The distal end 142 further includes apair of cutout regions 162 flanking the flange 158 (one cutout region162 on either side of the flange 158) that are each sized anddimensioned to receive one of the proximal extensions 170 of the distalbody portion 136, while allowing relative movement between the proximalbody portion 134 and distal body portion 136 (e.g. partial rotationabout the axis of the hinge pin 176).

The distal body portion 136 (shown by way of example in FIGS. 12-14) hasa proximal end 164, a distal portion 166 including a distal end 167, andan enlarged cutout section 168 positioned between the proximal end 164and distal portion 166 that primarily functions to reduce the amount ofmaterial used (and therefore the weight of the retractor). As will bedescribed in detail below, the proximal end 164 includes structure thatforms part of the hinge joint 138, while the distal portion 166 includesstructure enabling the coupling of the retractor arms 137, 139 to theretractor body 112, as well as structure related to the first bladeholder assembly 122. The proximal end 164 includes a pair of proximalextensions 170 extending in a proximal direction from the proximal end164 and spaced apart laterally by a distance that corresponds generallyto the width of the flange 158, thereby creating a void 172 between theproximal extensions 170 that is sized and configured to receive theflange 158 therein. Each proximal extension 170 includes a lateralaperture 174 sized and configured to interact with the hinge pin 176 andpositioned to be coaxial with the transverse through-hole 160 of theflange 158 when the flange 158 is positioned within the void 172.

The hinge joint 138 comprises the flange 158 of the proximal bodyportion 134, the proximal extensions 170 of the distal body portion 136,and a hinge pin 176 that secures the proximal body portion 134 to thedistal body portion 136 and provides a cylindrical surface about whichboth the proximal body portion 134 (via flange 158) and distal bodyportion 136 (via proximal extensions 170) may rotate. The hinge pin 176comprises a cylindrical shaft 178 having cylindrical head 180 at one endthat has a diameter greater than the diameter of the shaft 178 and athreaded aperture (not shown) at the other end (see FIG. 11). Thethreaded aperture of the shaft 178 is configured to mate with a hingescrew 182, and particularly a threaded post 184 thereof. The hinge screw182 futher comprises a head portion 186 including a driver recess (notshown) for engagement with a driver instrument. Each lateral aperture174 includes a circumferential ledge 188 positioned therein. Thecircumferential ledges 188 enable the passage of the cylindrical shaft178 therethrough but not the cylindrical head 180 of the hinge pin 176or the head portion 186 of the hinge screw 182. The hinge screw 182 maybe actuated by a driver such that rotation in a clockwise directiondraws the cylindrical head 180 of the hinge pin 176 and head portion 186of the hinge screw 182 toward one another, which due to their respectiveinteraction with the circumferential ledges 188 creates a compressiveforce acting on the proximal extensions 170 and flange 158, effectively“tightening” the construct to secure the proximal and distal bodyportions 134, 136 in a desired angular relationship. The angle may bere-adjusted after rotating the hinge screw 182 in a counterclockwisedirection to “loosen” the construct by relieving the compressive forceon the proximal extensions 170 and flange 158.

The distal portion 166 includes a generally planar superior surface 190,a generally planar inferior surface 192, and a protrusion 194 extendingvertically from the superior surface 190. The vertical protrusion 194 ispositoned adjacent to the enlarged cutout section 168 along thelongitudinal axis 1, and has a pair of threaded apertures 196 formedtherein in a transverse direction relative to the longitudinal axis. Thethreaded apertures 196 are each configured to receive the threaded post260 of an arm cap hinge screw 240 (see e.g. FIG. 15). The verticalprotrusion may also include a transverse through-hole 198 formed thereinto reduce the amount of material used to manufacture the retractor body112 (thereby reducing the weight of the device). The superior surface190 includes first and second concave recesses 200, 202 positioned oneither side of the distal body portion 136 adjacent to the verticalprotrusion 194. The concave recesses 200, 202 are sized and configuredto receive at least a portion of the generally spherical proximal ends226 of the first and second retractor arms 137, 139, respectively. Thesuperior surface 190 further includes a pair of vertically-orientedthreaded apertures 204 positioned adjacent the concave recesses 200,202, each configured to receive the threaded post 266 of an arm cap lockscrew 242 (see e.g. FIG. 15).

The distal end 167 of the distal portion 166 comprises the blade holder124 which includes a blade aperture 206 extending vertically through theblade holder 124, the blade aperture 206 being sized and configured toreceive the first retractor blade 120 therein. The superior surface 190further includes a generally cylindrical recess 208 formed therein andpositioned on the longitudinal axis immediately adjacent the bladeaperture 206 such that the blade aperture 206 and recess 208 areadjoining via a pass-through 210. The generally cylindrical recess 208is sized and configured to receive at least a portion of the bladeadjustment member 294 (see FIG. 17). The cylindrical recess 208 furtherincludes a bottom surface 212 having a circular aperture 214 extendingtherethrough, the diameter of the aperture 212 being less than thediameter of the cylindrical recess 208. The inferior surface 192 has ashaped recess 216 formed therein about the inferior egress of thecircular aperture 214. The inferior recess 216 has a peripheral shapecorresponding to the peripheral shape of the bottom plate 298, andincludes a threaded aperture 218 formed therein to receive a threadedpost portion of a bottom plate lock screw (not shown). A pair of lateralcutout sections 220 are provided laterally adjacent to the cylindricalrecess 208, for example to provide increased visibility of the operativecorridor for the surgeon.

FIGS. 11 and 15-16 illustrate the components related to the retractorarms 137, 139 in more detail. Specifically, FIG. 11 illustrates allcomponents in exploded form. FIG. 15 illustrates the components relatedto one retractor arm (e.g. second retractor arm 139) in exploded form.FIG. 16 illustrates an arm cap 238 in isolation. It should be understoodthat the first and second retractor arms 137, 139 and theircorresponding assembly components are either identical to or mirrorimages of each other. Therefore, for the purpose of illustration and inthe interest of brevity, like elements and assembly components have beenassigned the same reference number. As previously described, the firstand second retractor arms 137, 139 extend from the distal body portion136 of the retractor body 112. By way of example, each retractor arm137, 139 is a generally “L”-shaped cylindrical member having a lateralportion 222 and a longitudinal portion 224 joined by a generallyperpendicular elbow junction 225. In the example shown, the lateralportion 222 comprises the proximal short segment of the “L” shape andterminates with a generally spherical proximal end 226. The longitudinalportion 224 comprises the distal long segment of the “L” shape andterminates with an axially-formed threaded aperture 228. The firstretractor arm 137 is positioned such that the generally sphericalproximal end 226 is received within the first concave recess 200, andthe second retractor arm 139 is positioned such that the generallyspherical proximal end 226 is received within the second concave recess202. In both cases, the lateral portion 222 extends generally laterallyfrom one side of the distal body portion 136 (e.g. transverse to thelongitudinal axis 1 and in opposite directions from each other), and thelongitudinal portion 224 extends distally in a direction generallyparallel to the longitudinal axis 1. An arm stop 230 is provided havinga threaded post 232 configured to mate with the threaded aperture 228and a head portion 234 having a diameter larger than the diameter of thelongitudinal portion 224 to provide translation stops for the second andthird blade holder assemblies 128, 132. A lock pin (not shown) may beprovided that extends transversely through lock pin apertures 236 in theretractor arms 137, 139 and an axially aligned aperture (not shown) inthe threaded post 232 to lock the arm stop 230 to the correspondingretractor arms 137, 139.

Each retractor arm 137, 139 is secured within the concave apertures 200,202, respectively, by way of an arm cap 238. The arm caps 238 arehingedly secured to the distal body portion 136 by way of arm cap hingescrews 240. As will be explained, the arm caps 238 allow for independentadjustability of each retractor arm 137, 139 and are capable of beinglocked in place (and also unlocked for readjustment) by way of the armcap lock screws 242. By way of example, each arm cap 238 has a superiorsurface 244, inferior surface 246, and an outward facing (e.g. away fromthe longitudinal axis 1) lateral surface 248. The superior surface 244includes a vertically-oriented, nonthreaded through-hole 250 (whichextends to the inferior surface 246) sized and configured to receive thepost 264 of an arm cap lock screw 242 therethrough. The inferior surface246 includes a concave recess 252 sized and configured to receive atleast a portion of the generally spherical proximal end 226 of one ofthe retractor arms 137, 139 therein. The lateral surface 248 includes alaterally-oriented through-hole 254 configured to receive the post 258of an arm cap hinge screw 240 therethrough.

When the arm caps 238 are placed in position on the distal body portion136, the laterally-oriented through-holes 254 are axially aligned withthe threaded apertures 196 on either side of the vertical protrusion194. Each arm cap hinge screw 240 includes a head 256 and a shaft 258including a distal threaded portion 260 extending from the head 256. Theshaft 258 is inserted through the lateral through-hole 254 such that thedistal threaded portion 260 is threadedly engaged with the threadedapertures 196. When the arm cap hinge screw 240 is fully inserted andthe arm cap lock screw 242 is in an “unlocked” position, the arm cap 238may pivot slightly about the shaft 258 of the arm cap hinge screw 240 inresponse to any adjustment of the retractor arms 137, 139. When the armcap lock screw 242 is in a “locked” position, the arm cap 238 does notmove.

Similarly, when the arm caps 238 are placed in position on the distalbody portion 136, the vertically-oriented through-holes 250 are axiallyaligned with the threaded apertures 204 on the superior surface 190 ofthe distal body portion 136. Each arm cap lock screw 242 includes a head262 and a shaft 264 including a distal threaded portion 266 extendingfrom the head 262. The head 262 comprises an enlarged member sized andconfigured to be manually manipulated by a user with or without the useof additional instrumentation. The shaft 264 is inserted through thevertical through-hole 250 such that the distal threaded portion 266 isthreadedly engaged with the threaded apertures 204. When the arm caplock screw 242 is nearly fully inserted but not tightened (e.g. in an“unlocked” position), the arm cap 238 may pivot slightly about the shaft258 of the arm cap hinge screw 240 in response to any adjustment of theretractor arms 137, 139. The adjustment of the retractor arms 137, 139is enabled by the interaction of the generally spherical proximal ends226 and the concave recesses 200, 202 of the distal body portion 136 andthe concave recesses 252 of the arm caps 238, and allows the lateralportion 222 of each retractor arm 137, 139 to experience a generallyconical range of motion limited by the lateral openings of theaforementioned concave recesses. Rotation of the retractor arms 137, 139is not limited. Thus, the distal ends of the retractor arms 137, 139(including the associated retractor blade assemblies 116, 118) may beindependently positionable and customizable to the specfic needs of theuser. When the arm cap lock screws 242 are fully tightened (e.g. in a“locked” position), the arm caps 238 exert a compressive force on theproximal ends 226 of the retractor arms 137, 139 within the concaverecesses 200, 202, 252, which in turn locks the retractor arms 137, 139in position.

With reference to FIGS. 17-23, the first blade assembly 114 includes afirst retractor blade 120, a first blade holder assembly 122, and ananchor pin 268. The first retractor blade 120 may be constructed havingany number of suitable features and dimensions. By way of example, thefirst retractor blade 120 is an elongated member having a generallyrectangular peripheral shape including a length dimension and a widthdimension. The first retractor blade 120 further includes a proximal end270, a distal end 272, a first side 274, and a second side 276. Duringuse, the proximal end 270 generally extends above the skin of a patient,the distal end 272 is positioned near the surgical target site, thefirst side 274 is inner-facing (e.g. facing towards the operativecorridor), and the second side 276 is outer-facing (e.g. facing awayfrom the operative corridor). The retractor blade 120 has a curvature inthe width dimesion such that the first side 274 has a generally concavecurvature and the second side 276 has a generally convex curvature. Thefirst side 274 includes one or more tracks for slideably receivingsurgical accessories such as a shim or light source (for example). Byway of example, the first side 274 includes a first track 278 extendingthe longitudinal length of the first blade 120 and positioned near themiddle of the first side 274, and a second track 280 positioned near onelateral edge of the first blade 120 and extending the longitudinallength of the blade. The tracks 278, 280 may have any cross-sectionalshape including but not limited to the dovetail shape shown by way ofexample in FIG. 22. The second side 276 includes a plurality oflaterally oriented ridges 282 positioned at the proximal end 270. Theridges 282 are positioned at an oblique angle relative to a longitudinalaxis of the first blade 120, with an angle complimentary to that of thehelical flange 304 of the blade adjustment member 294.

The first retractor blade 120 further includes a longitudinal aperture284 extending the longitudinal length of the blade 120 and positioned onthe side opposite the side of the second track 280. The longitudinalaperture 284 is size and configured to receive the anchor pin 268 (e.g.K-wire, Steinman pin, etc.) therethrough. A clip 286 configured toreleasably hold the anchor pin 268 in place is provided at the proximalend 270 of the first retractor blade 120. The clip includes a receptacle288 configured to engage the engagement recess 324 of the anchor pin 268in a snap-fit manner (for example). The clip 286 is secured to theretractor blade 120 with a lock screw 290 that is threadedly receivedwith a lock screw aperture 292 positoned next to the longitudinalaperture 284.

The first retractor blade 120 is curved toward the second side 276 atthe distal end 272. This enables the retractor blade 120 to gentlyengage and move anatomical structure (e.g. muscles, blood vessels, etc)away from the surgical target site as the retractor blade is adjusted.

The first blade holder assembly 122 includes a blade holder 124, bladeadjustment member 294, lock screw 296, and bottom plate 298. The bladeholder 124 has been described above with reference to FIGS. 12-14. Byway of example, the blade adjustment member 294 comprises a head portion300 and a generally cylindrical body portion 302 having a helical flange304 extending around the periphery of the body portion 302. The headportion 300 comprises a shaped member sized and configured to bemanually manipulated by a user with or without the use of additionalinstrumentation. The head portion 300 may have any shape suitable toenable a user to apply torque to the blade adjustment member 294,including but not limited to the diamond shape shown by way of examplein FIG. 17. The body portion 302 is sized and configured to be receivedwithin the cylindrical recess 208 of the retractor body 112 such that aportion of the helical flange 304 extends through the pass-through 210into the blade aperture 206 when the blade adjustment member 294 isseated within the cylindrical recess 208 and engages the ridges 282 ofthe first retractor blade 120 when the first retractor blade 120 is inthe blade aperture 206. The engagement of the helical flange 304 andridges 282 is in a generally threaded manner such that when the bladeadjustment member 294 is rotated in one direction (e.g. clockwise), thehelical flange 304 interacts with the ridges 282 to adjust the firstretractor blade 120 vertically upward, and when the blade adjustmentmember 294 is rotated in the opposite direction (e.g.counter-clockwise), the helical flange 304 interacts with the ridges 282to adjust the first retractor blade 120 vertically downward. In thismanner, the length of the blade 120 that extends below the skin incisionmay be manually adjusted by the user. The blade adjustment member 294further comprises a nonthreaded lumen 306 exending verticallytherethough, the nonthreaded lumen 306 sized and configured to allowpassage of the lock screw 296.

The lock screw 296 has a head 308 including a driver recess 310configured to engage a driver instrument and a threaded shaft 312configured to threadedly engage the threaded aperture 314 of the bottomplate 298. The bottom plate 298 has a peripheral shape corresponding tothe shape of the shaped recess 216 of the retractor body 112 (FIG. 13),and threaded interaction between threaded shaft 312 and the threadedaperture 314 results in the lock screw 296 holding the bottom plate 298within the shaped recess 216, thereby securing the blade adjustmentmember 294 to the retractor body 112. Once the lock screw 296 has beenfully inserted, a lock pin 316 (see FIG. 11) may be inserted throughlock pin aperture 318 (and axially aligned lock pin apertures (notshown) in the lock screw 296 and threaded aperture 314) to lock thefirst blade holder assembly 122 to the retractor body 112. The bottomplate 298 further includes an aperture 320 formed therein adjacent thethreaded aperture 314 to receive a head portion of a bottom plate lockscrew (not shown).

With reference to FIG. 23, the anchor pin 268 by way of example onlycomprises a head 322 including an engagement recess 324, elongated shaft326, and distal tip 328. The engagement recess 324 is sized andconfigured to be releasably held in the receptacle 288 of the clip 286.The elongated shaft 326 may be generally cylindrical and sized to extendthrough the longitudinal aperture 284 of the first retractor blade 120.The distal tip 328 has a generally pointed end that allows the anchorpine to be self-tapping. The elongated shaft 326 has a length dimensionthat is greater than the length dimension of the first retractor blade120, such that the head 322 is positioned proximal of the proximal end270 of the first blade 120 and the distal tip 328 extends distally ofthe distal end 272 of the first blade 120, which enables the distal tip328 to dock or otherwise temporarily register the distal end 272 of thefirst blade 120 relative to the surgical target site (e.g. by extendingthe anchor pin 268 into the adjacent vertebral bodies and/or the discspace). For example, during a retroperitoneal surgical approach to theL5-S1 disc space, the anchor pin 268 may dock to the L5 vertebra, andremain docked for the duration of the procedure. This advantageouslymaintains the barrier between the surgical target site and thesurrounding vasculature.

With reference to FIGS. 24-36, the second blade assembly 116 includes asecond retractor blade 126 and a second blade holder assembly 128. Thesecond retractor blade 126 may be constructed having any number ofsuitable features and dimensions. By way of example, the secondretractor blade 126 is an elongated member having a generallyrectangular peripheral shape including a length dimension and a widthdimension. The second retractor blade 126 further includes a proximalend 330, a distal end 332, a first side 334, and a second side 336.During use, the proximal end 330 generally extends above the skin of apatient, the distal end 332 is positioned near the surgical target site,the first side 334 is inner-facing (e.g. facing towards the operativecorridor), and the second side 336 is outer-facing (e.g. facing awayfrom the operative corridor). The second blade 126 has a curvature inthe width dimesion such that the first side 334 has a generally concavecurvature and the second side 336 has a generally convex curvature. Byway of example, the first side 334 includes a generally smooth surface.The second side 336 includes a plurality of laterally oriented ridges338 positioned at the proximal end 330. The ridges 338 are positionedtransversely relative to a longitudinal axis of the second blade 126,and are sized and configured to interact with the gear member 402 of theblade adjustment member 366.

In the example shown and described herein, the second retractor blade126 has three distal curves 340, 342, 344 that in effect laterallyoffset the distal end 332 relative to the proximal end 330 whilemaintaining the distal end 332 in a generally parallel orientationrelative to the proximal end 330 and also forming a hook feature 346 atthe distal tip 348. The first distal curve 340 is curved in thedirection extending away from the first side 334. The second distalcurve 342 is in the opposite direction resulting in a portion of thedistal end 332 being offset but generally parallel relative to theproximal end 330. The third distal curve 344 is curved in the directionof the second side 336, resulting in the formation of a hook feature 346at the distal tip 348. This enables the second blade 126 to initiallyavoid, then gently engage and move anatomical structure (e.g. muscles,blood vessels, etc.) away from the surgical target site as the secondblade 126 is adjusted. The distal end 332 further includes a pair oflongitudinal apertures 350 extending the longitudinal length of theoffset portion of the distal end 332 and positioned on either side thefirst side 334. The longitudinal apertures 350 are each sized andconfigured to receive an anchor pin 352 therethrough. By way of exampleonly, each anchor pin 352 includes a head 354 having a threaded post 356extending proximally therefrom, an elongated shaft 358, and a purchaseelement 360 at the distal tip of the elongated shaft 358. The one ormore anchor pins 352 enable the distal end 332 to dock or otherwisetemporarily register the distal end 332 of the second blade 126 relativeto the surgical target site (e.g. by extending into the adjacentvertebral bodies and/or the disc space). For example, during aretroperitoneal surgical approach to the L5-S1 disc space, the pins 352may dock to the L5 vertebra, and remain docked for the duration of theprocedure. This advantageously maintains the barrier between thesurgical target site and the surrounding vasculature.

The various components of the second blade holder assembly 128 areillustrated in further detail in FIGS. 27-36. By way of example only,the second blade holder assembly 128 includes a collar 362, anadjustment post 364, a blade adjustment member 366, a lock screw 368,and a tulip assembly 370. With reference to FIGS. 31-32, the collar 362includes a superior surface 372, inferior surface 374, and a lateralsurface 376 extending around the periphery of the collar 362 between thesuperior surface 372 and inferior surface 374. The collar 362 furtherincludes a blade aperture 378 extending vertically through the collar362 between the superior and inferior surfaces 372, 374, the bladeaperture 378 being sized and configured to receive the second retractorblade 126 therein. The superior surface 372 further includes a firstthreaded aperture 380 formed therein at a first oblique angle and asecond threaded aperture 382 formed therein at second oblique angle. Thefirst threaded aperture 380 is configured to receive the threaded post392 of the adjustment post 364. The second threaded aperture 382 isconfigured to receive the treaded shaft 458 of the tulip connector 420.The lateral surface 376 includes a generally cylindrical recess 384formed therein and extending in a transverse direction relative to thelongitudinal axis of the blade aperture 378 such that the blade aperture378 and recess 384 adjoin via a pass-through 386. The generallycylindrical recess 384 is sized and configured to receive at least aportion of the blade adjustment member 366 therein. The lateral surface376 further includes a threaded aperture 388 extending from the lateralsurface 376 through to the blade aperture 378. The threaded aperture 388is sized and confugured to engage the threaded shaft 414 of the lockscrew 368 such that at least a portion of the threaded shaft 414 extendsinto the blade aperture 378 (e.g. FIG. 41). By way of example only, thethreaded aperture 388 is positioned at one corner of the collar 362 andextends into the blade aperture 378 at an oblique angle relative to thetransverse direction. By way of example, each of the corners and edgesof the collar 362 may be rounded, chamfered, or otherwised smoothed overto reduce the impact on surrounding body tissue.

With primary reference to FIG. 30, the adjustment post 364 by way ofexample only includes an elongated shaft 390, a distally-extendingthreaded post 392, and a shaped proximal end 394. The elongated shaft390 is sized and configured to enable manual adjustment of the angularorientiation of the collar 362, and by extension the second blade 130,by acting as a lever, a handle, and an attachement point for additionaltorque-applying instrumentation and/or insertion handle. The theadedpost 392 extends distally from the elongated shaft 390 and is configuredto mate with the first threaded aperture 380 of the collar 362. Theshaped proximal end 394 may have any shape or configuration that enablesthe proximal end 394 to mate with a suitable torque-applying instrumentand/or insertion handle (not shown).

By way of example, the blade adjustment member 366 comprises a headportion 396 positioned at a proximal end, a neck portion 398 positioneddistally adjacent the head portion, a cylindrical shaft 400 extendingdistally of the neck portion, and a circular gear member 402 positionedat the distal end of the shaft 400. The head portion 396 comprises ashaped member sized and configured to be manually manipulated by a userwith or without the use of additional instrumentation. The head portion396 may have any shape suitable to enable a user to apply torque to theblade adjustment member 366, including but not limited to the diamondshape shown by way of example in FIG. 30. The neck portion 398, shaft400, and gear member 402 are sized and configured to be received withinthe cylindrical recess 384 of the collar 362 such that a portion of thegear member 402 extends through the pass-through 386 into the bladeaperture 378 when the blade adjustment member 366 is seated within thecylindrical recess 384 (e.g. FIG. 28). The gear member 402 engages theridges 338 of the second retractor blade 126 when the second blade 126is in the blade aperture 378. The engagement of the gear member 402 andridges 338 is such that when the blade adjustment member 366 is rotatedin one direction (e.g. clockwise), the second retractor blade 126 isvertically adjusted downward, and when the blade adjustment member 366is rotated in the opposite direction (e.g. counter-clockwise), thesecond retractor blade 126 is vertically adjusted upward. In thismanner, the length of the blade 126 that extends below the skin incisionmay be manually adjusted by the user. As best seen in FIG. 36, the neckportion 398 further comprises a circumferential recess 404 configured toreceive at least a portion of a pair of locking pins 406 which extendthrough locking pin apertures 408 in the superior and inferior surfaces372, 374 of the collar 362. The locking pins 406 prevent ejection of theblade adjustment member 366 while allowing for unencumbered rotationthereof.

The lock screw 368 has a head 410 including a driver recess 412configured to engage a driver instrument and a threaded shaft 414configured to threadedly engage the threaded aperture 388 of the collar362. The head 410 further comprises a plurality of ridges 416 disposedgenerally parallel to the axis of the threaded shaft 414 and dispersedabout the circumference of the head 410. The ridges 416 provide africtional engagement surface for a user in the event that the lockscrew 368 is hand-acutated. The distal tip of the threaded shaft 414 isconfigured to engage the second blade 126 when the second blade 126 ispositioned within the blade aperture 378 and has been adjusted to thesurgeon's preference. When the lock screw 368 is employed, the threadedshaft 414 exerts a force on the blade 126 which prevents the blade 126from moving within the blade aperture 378 until the force has beenalleviated.

With primary reference to FIGS. 30 and 33-35, the tulip assembly 370includes a tulip 418, a tulip connector 420, a saddle 422, a swivelclamp 424, a hinge pin 426, and a tulip screw 428. By way of exampleonly, the tulip 418 includes a base 430 and a pair of opposing first andsecond upstanding arms 432, 434 extending in a vertical direction awayfrom the base 430 and separated by a distance generally corresponding tothe diameter of the first retractor arm 137. The base 430 includes apair of concave surfaces 436 disposed between the upstanding arms 432,434 that, in combination with the upstanding arms 432, 434, form part ofan arm channel 438 configured to receive the first retractor arm 137upon final tightening of the construct. The base 430 further includes acentral aperture 440 extending vertically therethrough, the centralaperture 440 including a distal opening 442 through which extends thethreaded shaft 458 of the tulip connector 420. The central aperture 440further includes a generally arcuate interior surface 444 proximallyadjacent the distal opening 442 and a circumferential shelf 446proximally adjacent the arcuate interior surface 444. The generallyarcuate interior surface 444 is sized and configured to receive thespherical head 454 of the tulip connector 420. The circumferential shelf446 extends into the central aperture 440 and engages an inferiorsurface 464 of the saddle 422.

The first upstanding arm 432 includes a recess 448 formed therein sizedand configured to receive a portion of the swivel clamp 424 therein, anda pair of axially aligned vertically-oriented pin apertures 450 a, 450 bpositioned on either side of the recess 448 and configured to receive atleast a portion of the hinge pin 426. The second upstanding arm 434includes a recess 452 formed therein on an inner-facing side, the recess452 sized and configured to receive a portion of the swivel clamp 424therein.

With primary reference to FIG. 35, the tulip connector 420 includes aspherical head 454 positioned at a proximal end, and a shaft 456extending distally from the spherical head 454, the shaft 456 includinga distal threaded portion 458 and a circumferential recess 460positioned adjacent the spherical head 454. The spherical head 454 issized and configured to nest within the central aperture 440 of thetulip 418 while the shaft 456 extends through the distal opening 442.The distal threaded portion 458 is configured to threadedly mate withthe second threaded aperture 382 of the collar 362. The interactionbetween the spherical head 454 and the generally arcuate interiorsurface 444 of the central aperture 440 enables the shaft 456 to havepolyaxial pivotability in that the shaft 456 (and by extension thecollar 362) is able to pivot in any direction as well as rotate aboutthe spherical head 454 prior to final tightening of the construct. Thisfeature ultimately allows the surgeon greater flexiblity whenpositioning the second retractor blade 126. The circumferential recess460 enables the shaft 456 to have a greater pivot angle by removingmaterial that might otherwise abut the distal opening 442.

By way of example only, the saddle 422 includes a superior surface 462having a concave curvature, a generally planar inferior surface 464, andan inferior recess 466 having a generally arcuate surface 468. Thesaddle 422 is generally cylindrical and configured to nest within thecentral aperture 440 of the tulip 418. The superior surface 462 isconfigured to engage the first retractor arm 137. The inferior surface464 is configured to engage the circumferential shelf 446, and thegenerally arcuate surface 468 of the inferior recess 466 is sized andconfigured to engage the spherical head 454 of the tulip connector 420.

The swivel clamp 424 includes a body portion 470 having a centralthreaded aperture 472 extending longidutionally therethrough and a hingeaperture 474 positioned toward one side of the body portion 470. Thecentral threaded aperture 472 is sized and configured to receive atleast a portion of the threaded shaft 482 of the tulip screw 428therein. The hinge aperture 474 is sized and configured to receive thehinge pin 426 therethrough. The hinge pin 426 comprises a generallycylindrical member sized and configured such that a first end isreceived within the superior pin aperture 450 a of the tulip 418, asecond end is received within the inferior pin aperture 450 b of thetulip 418, and a middle portion extends through the hinge aperture 474of the swivel clamp 424. In this fashion, the swivel clamp 424 ishingedly coupled to the tulip 418 and capable of pivoting about thehinge pin 426. The tulip screw 428 has a head 476 including a driverrecess 478 configured to engage a driver instrument and a threaded shaft480 configured to threadedly engage the central threaded aperture 472 ofthe swivel clamp 424. By way of example only, the head 476 furthercomprises a peripheral shape providing a frictional engagement surfacefor a user in the event that the tulip screw 428 is hand-acutated. Thedistal tip 482 of the threaded shaft 480 is configured to engage thefirst retractor arm 137 upon final tightening of the blade holderassembly 128.

The swivel clamp 424 allows for efficient coupling (and/or uncoupling)of the second blade holder assembly 128 to the first retractor arm 137at any time during the procedure, including but not limited to after thesecond retractor blade 126 has been inserted into the operativecorridor. This is because the tulip screw 428 may be precoupled to theswivel clamp 424 and the swivel clamp 424 may pivot about the hinge pin426, allowing the first retractor arm 137 to be inserted into the armchannel 438 of the tulip 418. Once the first retractor arm 137 is placedwithin the arm channel 438, the swivel clamp 424 is pivoted back intoposition acting as a crossbeam spanning between the first and secondupstanding arms 432, 434 (with at least a portion of the swivel clamp424 occupying space within each of the recesses 448, 452), therebypreventing ejection of the first retractor arm 137 from the arm channel438. Once this occurs, and the tulip assembly 370 is positionedaccording to the surgeon's preferences, the tulip screw 428 may berotated to achieve final tightening of the construct. Upon finaltightening, the tulip screw 428 applies compressive force (by way ofdistal tip 482) on the retractor arm 137, which in turn applies theforce to the saddle 422, which compresses the spherical head 454 of thetulip connector 420 against the generally arcuate surface 444 of thetulip 418, thereby locking the angle of the tulip connector 420 in placerelative to the tulip 418.

FIGS. 37-49 illustrate an example of the third blade assembly 118according to one aspect of the disclosure. With initial reference toFIGS. 37-39, and by way of example only, the third blade assembly 118includes a third retractor blade 130 and a third blade holder assembly132. The third retractor blade 130 may be constructed having any numberof suitable features and dimensions. By way of example, the thirdretractor blade 130 is an elongated member having a generallyrectangular peripheral shape including a length dimension and a widthdimension. The third retractor blade 130 further includes a proximal end484, a distal end 486, a first side 488, and a second side 490. Duringuse, the proximal end 484 generally extends above the skin of a patient,the distal end 486 is positioned near the surgical target site, thefirst side 488 is inner-facing (e.g. facing towards the operativecorridor), and the second side 490 is outer-facing (e.g. facing awayfrom the operative corridor). The third blade 130 has a curvature in thewidth dimesion such that the first side 488 has a generally concavecurvature and the second side 490 has a generally convex curvature. Thefirst side 488 includes one or more tracks 492 for slideably receivingsurgical accessories such as a shim or light source (for example). Byway of example, the first side 488 includes a single track 492 extendingthe longitudinal length of the third blade 130 and positioned near themiddle of the first side 488. The track 492 may have any cross-sectionalshape including but not limited to the dovetail shape shown best by wayof example in FIG. 49. The second side 490 includes a plurality oflaterally oriented ridges 494 positioned at the proximal end 484. Theridges 494 are positioned transversely relative to a longitudinal axisof the third blade 130, and are sized and configured to interact withthe gear member 544 of the blade adjustment member 508. The thirdretractor blade 130 further includes a longitudinal aperture 496extending the longitudinal length of the blade 130 and positioned on oneside the track 492. The longitudinal aperture 496 may be sized andconfigured to receive therethrough a surgical accessory, for example asuction hose.

In the example shown and described herein, the third retractor blade 130has a pair of distal curves 498, 500 that in effect laterally offset thedistal end 486 relative to the proximal end 484 while maintaining thedistal end 486 in a generally parallel orientation relative to theproximal end 484. The first distal curve 498 is curved toward the secondside 490 and includes the distal terminus of the longitudinal aperture496. The second distal curve 500 is curved back toward the first side488. This enables the third blade 130 to gently engage and moveanatomical structure (e.g. muscles, blood vessels, etc) away from thesurgical target site as the third blade 130 is adjusted. The distal end486 further includes a purchase element 502 extending distally therefromwhich enables the distal end 486 to dock or otherwise temporarilyregister the distal end 486 of the third blade 130 relative to thesurgical target site (e.g. by extending into the adjacent vertebralbodies and/or the disc space). For example, during a retroperitonealsurgical approach to the L5-S1 disc space, the purchase element 502 maydock to the sacrum, and remain docked for the duration of the procedure.This advantageously maintains the barrier between the surgical targetsite and the surrounding vasculature. By way of example, the purchaseelement 502 may be any structure suitable for achieving purchase in bone(or disc space registration), including but not limited to a tack,wedge, pin, screw, and nail.

The third blade holder assembly 132 includes a collar 504, an adjustmentpost 506, a blade adjustment member 508, a lock screw 510, and a tulipassembly 512. With reference to FIGS. 44-45, the collar 504 includes asuperior surface 514, inferior surface 516, and a lateral surface 518extending around the periphery of the collar 504 between the superiorsurface 514 and inferior surface 516. The collar 504 further includes ablade aperture 520 extending vertically through the collar 504 betweenthe superior and inferior surfaces 514, 516, the blade aperture 520being sized and configured to receive the third retractor blade 130therein. The superior surface 514 further includes first threadedaperture 522 formed therein at a first oblique angle and a secondthreaded aperture 524 formed therein at second oblique angle. The firstthreaded aperture 522 is configured to receive the threaded post 534 ofthe adjustment post 506. The second threaded aperture 524 is configuredto receive the treaded shaft 600 of the tulip connector 562. The lateralsurface 518 includes a generally cylindrical recess 526 formed thereinand extending in a transverse direction relative to the longitudinalaxis of the blade aperture 520 such that the blade aperture 520 andrecess 526 adjoin via a pass-through 528. The generally cylindricalrecess 526 is sized and configured to receive at least a portion of theblade adjustment member 508 therein. The lateral surface 518 furtherincludes a threaded aperture 530 extending from the lateral surface 518through to the blade aperture 520. The threaded aperture 530 is sizedand confugured to engage the threaded shaft 556 of the lock screw 510such that at least a portion of the threaded shaft 556 extends into theblade aperture 520 (e.g. FIG. 41). By way of example only, the threadedaperture 530 is positioned at one corner of the collar 504 and extendsinto the blade aperture 520 at an oblique angle relative to thetransverse direction. By way of example, each of the corners and edgesof the collar 504 may be rounded, chamfered, or otherwised smoothed overto reduce the impact on surrounding body tissue.

With primary reference to FIG. 43, the adjustment post 506 by way ofexample only includes an elongated shaft 532, a distally-extendingthreaded post 534, and a shaped proximal end 536. The elongated shaft532 is sized and configured to enable manual adjustment of the angularorientiation of the collar 504, and by extension the third blade 130, byacting as a lever, a handle, and an attachment point for additionaltorque-applying instrumentation and/or insertion handle. The theadedpost 534 extends distally from the elongated shaft 532 and is configuredto mate with the threaded aperture 522 of the collar 504. The shapedproximal end 536 may have any shape or configuration that enables theproximal end 536 to mate with a suitable torque-applying instrumentand/or insertion handle (not shown).

By way of example, the blade adjustment member 508 comprises a headportion 538 positioned at a proximal end, a neck portion 540 positioneddistally adjacent the head portion, a cylindrical shaft 542 extendingdistally of the neck portion, and a circular gear member 544 positionedat the distal end of the shaft 542. The head portion 538 comprises ashaped member sized and configured to be manually manipulated by a userwith or without the use of additional instrumentation. The head portion538 may have any shape suitable to enable a user to apply torque to theblade adjustment member 508, including but not limited to the diamondshape shown by way of example in FIG. 40. The neck portion 540, shaft542, and gear member 544 are sized and configured to be received withinthe cylindrical recess 526 of the collar 504 such that a portion of thegear member 544 extends through the pass-through 528 into the bladeaperture 520 when the blade adjustment member 508 is seated within thecylindrical recess 526 (e.g. FIG. 41). The gear member 544 engages theridges 494 of the third retractor blade 130 when the third blade 130 isin the blade aperture 520. The engagement of the gear member 544 andridges 494 is such that when the blade adjustment member 508 is rotatedin one direction (e.g. clockwise), the third retractor blade 130 isvertically adjusted downward, and when the blade adjustment member 508is rotated in the opposite direction (e.g. counter-clockwise), the thirdretractor blade 130 is vertically adjusted upward. In this manner, thelength of the blade 130 that extends below the skin incision may bemanually adjusted by the user. The neck portion 540 further comprises acircumferential recess 546 configured to receive at least a portion of apair of locking pins 548 which extend through locking pin apertures 550in the superior and inferior surfaces 514, 516 of the collar 504. Thelocking pins 548 prevent ejection of the blade adjustment member 508while allowing for unencumbered rotation thereof.

The lock screw 510 has a head 552 including a driver recess 554configured to engage a driver instrument and a threaded shaft 556configured to threadedly engage the threaded aperture 530 of the collar504. The head 552 further comprises a plurality of ridges 558 disposedgenerally parallel to the axis of the threaded shaft 556 and dispersedabout the circumference of the head 552. The ridges 558 provide africtional engagement surface for a user in the event that the lockscrew 510 is hand-acutated. The distal tip of the threaded shaft 556 isconfigured to engage the third blade 130 when the third blade 130 ispositioned within the blade aperture 520 and has been adjusted to thesurgeon's preference. When the lock screw 510 is employed, the threadedshaft 556 exerts a force on the blade 130 which prevents the blade 130from moving within the blade aperture 520 until the force has beenalleviated.

With primary reference to FIGS. 43 and 46-47, the tulip assembly 512includes a tulip 560, a tulip connector 562, a saddle 564, a swivelclamp 566, a hinge pin 568, and a tulip screw 570. By way of exampleonly, the tulip 560 includes a base 572 and a pair of opposing first andsecond upstanding arms 574, 576 extending in a vertical direction awayfrom the base 572 and separated by a distance generally corresponding tothe diameter of the second retractor arm 139. The base 572 includes apair of concave surfaces 578 disposed between the upstanding arms 574,576 that, in combination with the upstanding arms 574, 576, form part ofan arm channel 580 configured to receive the second retractor arm 139upon final tightening of the construct. The base 572 further includes acentral aperture 582 extending vertically therethrough, the centralaperture 582 including a distal opening 584 through which extends thethreaded shaft 600 of the tulip connector 562. The central aperture 582further includes a generally arcuate interior surface 586 proximallyadjacent the distal opening 584 and a circumferential shelf 588proximally adjacent the arcuate interior surface 586. The generallyarcuate interior surface 586 is sized and configured to receive thespherical head 596 of the tulip connector 562. The circumferential shelf588 extends into the central aperture 582 and engages an inferiorsurface 606 of the saddle 564.

The first upstanding arm 574 includes a recess 590 formed therein sizedand configured to receive a portion of the swivel clamp 566 therein, anda pair of axially aligned vertically-oriented pin apertures 592 a, 592 bpositioned on either side of the recess 590 and configured to receive atleast a portion of the hinge pin 568. The second upstanding arm 576includes a recess 594 formed therein on an inner-facing side, the recess594 sized and configured to receive a portion of the swivel clamp 566therein.

The tulip connector 562 includes a spherical head 596 positioned at aproximal end, and a shaft 598 extending distally from the spherical head596, the shaft 598 including a distal threaded portion 600 and acircumferential recess 602 positioned adjacent the spherical head 596.The spherical head 596 is sized and configured to nest within thecentral aperture 582 of the tulip 560 while the shaft 598 extendsthrough the distal opening 584. The distal threaded portion 600 isconfigured to threadedly mate with the second threaded aperture 524 ofthe collar 504. The interaction between the spherical head 596 and thegenerally arcuate interior surface 586 of the central aperture 582enables the shaft 598 to have polyaxial pivotability in that the shaft598 (and by extension the collar 504) is able to pivot in any directionas well as rotate about the spherical head 596 prior to final tighteningof the construct. This feature ultimately allows the surgeon greaterflexiblity when positioning the third retractor blade 130. Thecircumferential recess 602 enables the shaft 598 to have a greater pivotangle by removing material that might otherwise abut the distal opening584.

By way of example only, the saddle 564 includes a superior surface 604having a concave curvature, a generally planar inferior surface 606, andan inferior recess 608 having a generally arcuate surface 610. Thesaddle 564 is generally cylindrical and configured to nest within thecentral aperture 582 of the tulip 560. The superior surface 604 isconfigured to engage the second retractor arm 139. The inferior surface606 is configured to engage the circumferential shelf 588, and thegenerally arcuate surface 610 of the inferior recess 608 is sized andconfigured to engage the spherical head 596 of the tulip connector 562.

The swivel clamp 566 includes a body portion 612 having a centralthreaded aperture 614 extending longidutionally therethrough and a hingeaperture 616 positioned toward one side of the main body portion 612.The central threaded aperture 614 is sized and configured to receive atleast a portion of the threaded shaft 622 of the tulip screw 570therein. The hinge aperture 616 is sized and configured to receive thehinge pin 568 therethrough. The hinge pin 568 comprises a generallycylindrical member sized and configured such that a first end isreceived within the superior pin aperture 592 a of the tulip 560, asecond end is received within the inferior pin aperture 592 b of thetulip 560, and a middle portion extends through the hinge aperture 616of the swivel clamp 566. In this fashion, the swivel clamp 566 ishingedly coupled to the tulip 560 and capable of pivoting about thehinge pin 568. The tulip screw 570 has a head 618 including a driverrecess 620 configured to engage a driver instrument and a threaded shaft622 configured to threadedly engage the central threaded aperture 614 ofthe swivel clamp 566. By way of example only, the head 618 furthercomprises a peripheral shape providing a frictional engagement surfacefor a user in the event that the tulip screw 570 is hand-acutated. Thedistal tip 624 of the threaded shaft 622 is configured to engage thefirst retractor arm 137 upon final tightening of the blade holderassembly 132.

The swivel clamp 566 allows for efficient coupling (and/or uncoupling)of the third blade holder assembly 132 to the second retractor arm 139at any time during the procedure, including but not limited to after thethird retractor blade 130 has been inserted into the operative corridor.This is because the tulip screw 570 may be precoupled to the swivelclamp 566 and the swivel clamp 566 may pivot about the hinge pin 568,allowing the second retractor arm 139 to be inserted into the armchannel 580 of the tulip 560. Once the second retractor arm 139 isplaced within the arm channel 580, the swivel clamp 566 is pivoted backinto position acting as a crossbeam spanning between the first andsecond upstanding arms 574, 576 (with at least a portion of the swivelclamp 566 occupying space within each of the recesses 590, 594), therebypreventing ejection of the second retractor arm 139 from the arm channel580. Once this occurs, and the tulip assembly 512 is positionedaccording to the surgeon's preferences, the tulip screw 570 may berotated to achieve final tightening of the construct. Upon finaltighening, the tulip screw 570 applies compressive force (by way ofdistal tip 624) on the retractor arm 139, which in turn applies theforce to the saddle 564, which compresses the spherical head 596 of thetulip connector 562 against the generally arcuate surface 586 of thetulip 560, thereby locking the angle of the tulip connector 562 in placerelative to the tulip 560.

The retractor systems 10, 110 may be used according to the methodologiesset forth in U.S. Pat. No. 9,451,940 forming part of this disclosure.More specifically, the retractor systems 10, 110 may be used during anynumber of described surgical approaches to the spine of a patient,including but not limited to a minimally invasive retroperitonealapproach to the L5-S1 disc space in order to perform a spinal fusionprocedure. During such a procedure, any number of suitable implants andinstrumentation may be used, including but not limited to those setforth in U.S. Pat. No. 9,451,940.

For example, during a retroperitoneal approach (e.g. such as describedin U.S. Pat. No. 9,451,940), the retractor 110 provides mechanicalprotection to ateries and vessels that go to the legs. Morespecifically, the retractor 110 may be positioned below the bifurcationof iliac arteries and vessels in order to first displace the vessels andarteries to provide exposure to the L5-S1 disc space, and then shieldthe vessels and arteries from damage during the procedure. The retractor110 of the present disclosure is employed after the surgeon hasestablished initial access to the surgical target site (e.g. L5-S1 discspace) via finger dissection and/or dilation. By way of example, whenthe retractor 110 is initially introduced, only the first retractorblade 120 may be coupled to the retractor body 112 as described above.The retractor arms 137, 139 are not initialy associated with either thesecond or third blade assemblies 116, 118, and may be pivoted and/orrotated away from the surgical site so as to be out of the way ofactivity in and around the surgical incision. The first retractor blade120 (coupled with the retractor body 112) is inserted through theoperative corridor until the distal end is near the L5 vertebra. Cautionis used to first avoid surrounding vasculature such as iliac arteries650 and veins 652 during insertion of the blade 120, and to use theblade to engage and displace the arteries and veins from the operativecorridor. When the first blade 120 is in position, an anchor pin 268 maybe used to dock the first blade 120 to the L5 vertebra, as shown by wayof example in FIG. 50. At this point (or before this point), theretractor body 112 may be coupled to the patient's bed via anarticulating arm (not shown) so that the retractor has stability inbeing secured to both the patient and the patient's bed.

Once the first blade 120 is in position, the second blade 126 may beempolyed in a similar fashion to the first blade 120. The second blade126 may be initially coupled to the second blade holder assembly 128.The second blade 126 is then introduced into the operative corridoruntil the distal end is near the surgical target site. The blade 126 isthen used to engage and displace surrounding arteries 654 and veins 656from the operative corridor, creating access to the L5-S1 disc space.The second blade 126 may then be coupled to the first retractor arm 137as described above. Additionally, an anchor pin may be used to dock thesecond blade 126 to the L5 vertebra, as shown by way of example in FIG.50.

Once the second blade 126 is in position, the third blade 130 may beempolyed in a nearly identical fashion to the second blade 126. Thethird blade 130 may be initially coupled to the third blade holderassembly 132. The third blade 130 is then introduced into the operativecorridor until the distal end is positioned near the surgical targetsite. The blade 130 may then be used to engage and displace anysurrounding tissue, for example the peritoneum 658. The blade 130 may bedocked to the sacrum using the purchase element 502 at the distal tip ofthe blade 130. Thus at this point, all three retractor blades 120, 126,128 are registered to bony structure within the patient and theretractor body 112 is secured to the patient's bed, which establishes asecure operative corridor that does not constantly need to be monitoredor maintained by human hands. Once the operative corridor has beenestablished providing safe access to the surgical target site (e.g.L5-S1 disc space), the surgical procedure may proceed.

The foregoing description, for the purpose of explanation, has beendescribed with reference to specific embodiments. However, theillustrative discussions above are not intended to be exhaustive or tolimit the invention to the precise forms disclosed. Many modificationsand variations are possible in view of the above teachings. Theembodiments were chosen and described in order to best explain theprinciples of the embodiments and its practical applications, to therebyenable others skilled in the art to best utilize the embodiments andvarious modifications as may be suited to the particular usecontemplated. Accordingly, the present embodiments are to be consideredas illustrative and not restrictive, and the invention is not to belimited to the details given herein, but may be modified within thescope and equivalents of any claims based on this disclosure.

Any of the features or attributes of the above the above describedembodiments and variations can be used in combination with any of theother features and attributes of the above described embodiments andvariations as desired. Various modifications, additions and otheralternative embodiments are possible without departing from the truescope and spirit. The embodiments presented herein were chosen anddescribed to provide an illustration of various principles of thepresent invention and its practical application to thereby enable one ofordinary skill in the art to utilize the invention in variousembodiments and with various modifications as are suited to theparticular use contemplated. All such modifications and variations arewithin the scope of the present invention as determined by any claimsbased on this disclosure when interpreted in accordance with the benefitto which they are fairly, legally, and equitably entitled.

What is claimed is:
 1. A surgical retractor system, comprising: aretractor body having a proximal end, a distal end, and a longitudinalaxis extending through the proximal and distal ends, the retractor bodyhaving at least one articulation joint along the longitudinal axis and apair of opposing first and second arm extensions pivotably coupledthereto, the first and second arm extensions configured to mate with thesecond and third blade assemblies; a first blade assembly, the firstblade assembly including a collar integrally formed with the retractorbody and positioned along the longitudinal axis at the distal end, thecollar configured to couple with a first retractor blade; a second bladeassembly removably coupled to the first arm extension, the second bladeassembly including a second retractor blade and a blade holder assembly,the blade holder assembly including a collar polyaxially coupled to thefirst arm extension; and a third blade assembly removably coupled to thesecond arm extension, the third blade assembly including a thirdretractor blade and a blade holder assembly, the blade holder assemblyincluding a collar polyaxially coupled to the second arm extension. 2.The system of claim 1, wherein the first blade assembly further includesa height adjustment member, the height adjustment member actuatable tocause the first retractor blade to translate vertically within thecollar.
 3. The system of claim 1, wherein the first blade assemblyfurther includes an anchor pin coupled with the first retractor blade,the anchor pin having a distal tip configured to gain purchase withinbone.
 4. The system of claim 1, wherein the second blade assemblyfurther includes a height adjustment member, the height adjustmentmember actuatable to cause the second retractor blade to translatevertically within the collar.
 5. The system of claim 1, wherein thesecond blade assembly further includes an anchor pin coupled with thesecond retractor blade, the anchor pin having a distal tip configured togain purchase within bone.
 6. The system of claim 1, wherein the secondblade assembly further comprises a coupling element positioned betweenthe collar and the first arm extension, the coupling element including areceptacle for receiving therein at least a portion of the first armextension and a hinged barrier moveable from a first position permittingat least one of ingress and egress into the receptacle to a secondposition preventing ingress and egress into the receptacle.
 7. Thesystem of claim 6, wherein the hinged barrier further comprises alocking element.
 8. The system of claim 7, wherein the locking elementis configured to: lock the hinged barrier in a closed configuration; andlock the polyaxial coupling in a selected angular orientation.
 9. Thesystem of claim 1, wherein the third blade assembly further includes aheight adjustment member, the height adjustment member actuatable tocause the third retractor blade to translate vertically within thecollar.
 10. The system of claim 1, wherein the third retractor bladefurther includes a distally located purchase element integrally formedwith the third retractor blade, the purchase element configured to gainpurchase within bone.
 11. The system of claim 1, wherein the third bladeassembly further comprises a coupling element positioned between thecollar and the second arm extension, the coupling element including areceptacle for receiving therein at least a portion of the second armextension and a hinged barrier moveable from a first position permittingat least one of ingress and egress into the receptacle to a secondposition preventing ingress and egress into the receptacle.
 12. Thesystem of claim 11, wherein the hinged barrier further comprises alocking element.
 13. The system of claim 12, wherein the locking elementis configured to: lock the hinged barrier in a closed configuration; andlock the polyaxial coupling in a selected angular orientation.
 14. Thesystem of claim 1, wherein the second retractor blade comprises anelongated element having a proximal end, a distal end, a longitudinalaxis, and at least two curvatures along the longitudinal axis resultingin the distal end being offset from and parallel to the longitudinalaxis.
 15. The system of claim 1, wherein the third retractor bladecomprises an elongated element having a proximal end, a distal end, alongitudinal axis, and at least two curvatures along the longitudinalaxis resulting in the distal end being offset from and parallel to thelongitudinal axis.
 16. A method of establishing an operative corridor toa surgical target site in a patient, comprising: providing a surgicalretractor system, comprising: a retractor body having a proximal end, adistal end, and a longitudinal axis extending through the proximal anddistal ends, the retractor body having at least one articulation jointalong the longitudinal axis and a pair of opposing first and second armextensions pivotably coupled thereto, the first and second armextensions configured to mate with the second and third bladeassemblies; a first blade assembly including a collar and a firstremovable purchase element, the collar integrally formed with theretractor body and positioned along the longitudinal axis at the distalend, the collar configured to couple with a first retractor blade, thefirst retractor blade having a proximal end and a distal end; a secondblade assembly attachable to the first arm extension, the second bladeassembly including a second retractor blade, a blade holder assembly,and a second removable purchase element, the second retractor bladehaving a proximal end and a distal end, the blade holder assemblyincluding a collar polyaxially coupled to the first arm extension; and athird blade assembly attachable to the second arm extension, the thirdblade assembly including a third retractor blade and a blade holderassembly, the third retractor blade having a proximal end, a distal end,and a integral purchase element positioned at the distal end, the bladeholder assembly including a collar polyaxially coupled to the second armextension; advancing the first retractor blade through a skin incisionformed in the patient until the distal end of the first retractor bladeis positioned adjacent the surgical target site; selectively maneuveringthe first retractor blade near the surgical target site to engage andreposition nearby blood vessels and/or body tissue away from thesurgical target site; docking the first retractor blade to a bonystructure adjacent the surgical target site by introducing the firstremovable purchase element into the bony structure; advancing the secondretractor blade through the skin incision until the distal end of thesecond retractor blade is positioned adjacent the surgical target site;selectively maneuvering the second retractor blade near the surgicaltarget site to engage and reposition nearby blood vessels and/or bodytissue away from the surgical target site; docking the second retractorblade to a bony structure adjacent the surgical target site byintroducing the second removable purchase element into the bonystructure; advancing the third retractor blade through the skin incisionuntil the distal end of the third retractor blade is positioned adjacentthe surgical target site; selectively maneuvering the third retractorblade near the surgical target site to engage and reposition nearbyblood vessels and/or body tissue away from the surgical target site; anddocking the third retractor blade to a bony structure adjacent thesurgical target site by introducing the integral purchase element intothe bony structure.
 17. The method of claim 16, further comprising thestep of attaching the second blade assembly to the first retractor arm.18. The method of claim 16, further comprising the step of attaching thethird blade assembly to the second retractor arm.